Pulse,jack and ALSA do AFAIK not (properly) support multi-user/multiseat systems.
i.e. systems where multiple users access the same hardware (if configured that way), should not be able to "spy" on each other (if configured that way) and should have restricted access to some devices (if configured that way).
This applies to the video part of pipewire as well.
Does/Will pipewire support (part of) this?